Embodiments of the present invention provide cross-coupled rectifiers that use near zero-threshold transistors in a switching topology, but provide a topology that avoids reverse conduction problems. Importantly, preferred embodiment rectifiers of the invention only provide a slightly increased on-resistance in each branch, while providing both very high operating efficiency and very low turn-on voltage. An embodiment of the invention is a voltage rectifier for the conversion of RF energy into DC voltage with a turn-on threshold voltages approaching 0V.